The architectural centerpiece of the 290,000-square-foot complex, just west of the campus of the Los Angeles County Museum of Art, would be a giant glass-enclosed dome, which Piano refers to as the "sphere" and the "soap bubble."

It would hold a 1,000-seat theater and be attached to the northern side of architect Albert C. Martin's 1939 May Co. building, which would be restored as part of the museum plan and hold exhibits on Hollywood history and the craft of filmmaking. A rear addition to the May Co. built in 1946 would be demolished to make way for the dome.

The local and international architectural precedents for the spherical theater are clear enough. They begin with the 1963 Cinerama Dome on Sunset Boulevard, by Welton Becket and Pierre Cabrol, and the dirigibles that once took off from this part of Wilshire Boulevard. They stretch back to experiments on geodesic domes by Buckminster Fuller and the work of the 18th century French architect Etienne-Louis Boullee.

Also plain to see is the architectural potential of the scheme if it is given a genuine chance to evolve and deepen over the next few months.

Piano speaks persuasively of the theater, which would be topped by a wide indoor plaza with a view of the Hollywood sign near the top of the dome, right beneath a soaring glass canopy, as a new civic gathering place for a city that has always had too few of them.

As he put it in a visit to The Times on Thursday, he also likes the notion of building an extensive movie museum in the same city where filmmaking was born.

But some fundamental details of the plan remain opaque. Whether the architectural concept will prove robust enough to survive the obstacles it faces between now and the museum's planned opening date of 2017 is the key question to pose at this point.

Indeed, the academy's interest in making the plans, which are now in the schematic design phase, public at this stage, before they are fully cooked, suggests that its leaders haven't studied in full the tumultuous history of ambitious architecture at the LACMA site.

If there is one lesson in that history, which in the last 15 years alone includes a derailed plan by Rem Koolhaas and two sub-par gallery buildings by Piano, the Broad Contemporary Art Museum and the Lynda and Stewart Resnick Pavilion, it is that fundraising, architectural ambition and curatorial goals have to be in lock step from the beginning of the design process for a project to succeed.

The ambition of the dome represents a kind of progress in itself for the academy. Its board has at least agreed on a single architectural vision to pitch to the public and potential donors.

But it remains unclear who would design the exhibition spaces and, most important of all, how the museum's architecture would relate to its curatorial mission.

Conflict between the architectural goals of Piano and Pali and whoever is chosen to design the exhibits is one potential pitfall. Another is the role that current and future Hollywood donors to the project might have in dictating the content or the emphasis of the galleries.

How the film museum would ultimately relate to the redesign of LACMA that Chief Executive Michael Govan is working on with the Swiss architect Peter Zumthor also remains to be seen, as those plans are not yet public.

For Piano, taking on the academy museum job seemed in part a way to salvage the imperfect architectural results of his 2004 master plan for the LACMA campus and his designs for BCAM and the Resnick Pavilion.

A central feature of that master plan is an east-west axis, which Piano refers to as an interior street, running just north of BCAM. But while the future of the May Co. building was unclear — for a time, Pali was working with LACMA to restore it for the museum's use, and a James Turrell artwork was planned for its rooftop — that street had no destination on its western end.

At the very least, accepting the academy commission gave Piano a chance to extend the territory of his master plan all the way west to Fairfax Avenue. One of the strengths of this preliminary design, in fact, is the way it is open and porous along Fairfax, allowing pedestrians to walk under the raised sphere of the theater and toward the center of the LACMA campus.

Where the May Co. building and the sphere come together is a kind of interstitial (and potentially dramatic) circulation space filled with stairs, escalators and elevators.